Articulated robots are widely used in assembly lines that assemble large apparatuses such as automobile assembly lines, but in electronic-circuit-component mounting machines, for example, an XY robot is used in the manner disclosed in PTL 1. Electronic-circuit-component mounting machines are generally machines that assemble electronic circuits by mounting a plurality of electronic circuit components, which are supplied from a plurality of component supply devices, onto a circuit board that is carried into a work region by a substrate conveyance device, but since high accuracy is required in the positioning of the electronic circuit components on the circuit board, XY robots that can easily secure high positioning accuracy are used.